This invention relates generally to internal combustion engines in lawn-cutting machines, and in particular, to a grass-cutting tractor incorporating improved operating features, as well as, an auxiliary generator for electrically powering other types of equipment.
Grass-cutting tractors are available in a wide variety of configurations including riding mowers, lawn tractors, garden tractors, so-called compact tractors and larger commercial tractors. A riding mower is often characterized by a rear-mounted, vertical shaft engine and is configured only for grass cutting. A lawn tractor is configured more like a conventional farm tractor in having a front mounted engine, rear driving wheels and an operator""s seat between the engine and the driving wheels. A lawn tractor is configured primarily for grass cutting but is likely to have towing capability and other non-ground-engaging implements, e.g., a snow blower or snow plow. A garden tractor is similar in many respects to a lawn tractor but, in addition, has a ground-engaging implement, e.g., a rotary tiller or toothed plow. A compact tractor and a commercial tractor are typically large lawn tractors that may be fitted with any of a variety of implements. As used in this specification, the phrases xe2x80x9clawn tractorxe2x80x9d and xe2x80x9cgrass-cutting tractorxe2x80x9d contemplate all of the foregoing.
Grass-cutting tractors have been popular for many years with property owners, residential and commercial alike. For lawns of smaller area, as in a residential setting, one might consider such a mower as a luxury. But as lawn area increases, mechanized mowing tends toward becoming a virtual necessity, at least in the view of the property owner. For example, mechanized mowing is a necessity for wide expanses of grass such as are found at golf courses
The control of a grass-cutting tractor involves manipulation of at least two aspects of the tractor""s operation, namely, the over-the-ground speed and the mower blade speed. A conventional approach to controlling both aspects is to set the engine speed (and, therefore, the blade speed) at a substantially maximum speed and controlling over-the-ground speed using a multiple-step mechanical transmission or an infinitely-variable hydrostatic transmission.
By way of example, U.S. Pat. No. 4,773,371 (Stenz) discloses a grass-cutting tractor wherein the engine operates at constant speed, irrespective of the horsepower required to cut grass. However, it can be appreciated that the running of the engine of the grass-cutting tractor at a constant, substantially-maximum speed has some disadvantages. By running the engine at substantially-maximum speed, the rate of engine wear per unit of tractor operating time is increased. Further, the running of the engine at substantially-maximum speed increases the noise generated by the grass-cutting tractor to an unnecessarily high level as compared to the noise level generated when operating the engine at less than maximum speed.
In addition to utilizing a grass-cutting tractor, property owners often times utilize other types of lawn care accessories or tools such as lawn edgers, blowers, electric chain saws and the like to maintain the aesthetic appearance of their property. These types of lawn care accessories require electrical power in order to operate. As such, the property owner must provide electrical power at the location where use of such lawn care accessories is required. Typically, electrical power is provided at a specific location on the property by use of an extension cord that runs from an electrical outlet to the location. Since grass-cutting tractors may be transported to any location on the property, it would be highly desirable to provide a source of electrical power on the grass-cutting tractor. Therefore, an improved grass-cutting tractor which addresses disadvantages of the prior art would be an important advance in this field of technology.
Therefore, it is a primary object and feature of the present invention to provide an improved grass-cutting tractor overcoming some of the problems and shortcomings of the prior art.
It is further object and feature of the present invention to provide an improved grass-cutting tractor which reduces the rate of engine wear for certain grass conditions.
It is a still further object and feature of the present invention to provide an improved grass-cutting tractor which reduces tractor noise for certain grass conditions.
It is a still further object and feature of the present invention to provide an improved grass-cutting tractor which also may be utilized as a source of electrical power.
It a still further object and feature of the present invention to provide an improved grass-cutting tractor which is easy to operate, whether cutting grass or transporting the tractor from place to place.
In accordance with the present invention, an improvement in a grass cutting tractor is provided. The grass cutting tractor includes an internal combustion engine and apparatus which changes engine speed. The improvement comprises the apparatus including a user manipulated mechanism having first, second and third operating positions. The second and third operating positions are each identified by a different grass-related mnemonic relating to the height of the grass to be cut.
The engine includes a throttle and an electrical device producing an outward signal that represents engine speed. The tractor includes an electronic controller having a microprocessor coupled to the throttle and to the mechanism. The second and third operating positions select second and third inputs, respectively, to the microprocessor. The engine speeds substantially correspond to predetermined speeds represented by the input selected.
It is contemplated to provide a panel having first, second and third actuators for selecting the first, second and third operating positions, respectively. Alternatively, a lever may be mounted to the lawn tractor for movement between the first, second and third operating positions. The grass-related mnemonics identifying the second and third operating positions are selected from the group of mnemonic including normal, heavy, medium, high, regular and tall. The first operating position is identified by an engine related mnemonic related to engine speed. The first, second and third operating positions correspond with first, second and third engine speeds, respectively.
A generator may be operatively connected to the engine for generating electrical power having a magnitude and a frequency. The user manipulated mechanism of the apparatus includes a fourth operating position. The fourth operating position being identified by a mnemonic relating to operation of the generator. The fourth operating position selects a predetermined input to the microprocessor and the engine speed substantially corresponds to a predetermined speed presented by the input.
In accordance with a further aspect of the present invention, a grass cutting tractor is provided. The grass-cutting tractor includes an internal combustion engine and an apparatus operatively connected to the engine for adjusting engine speed. The apparatus includes a user manipulated mechanism having a plurality of operating positions. At a least a portion of the plurality of operating positions is identified by different speed related mnemonics relating to the grass to be cut.
The engine includes a throttle and a tractor includes an electronic controller having a microprocessor coupled to the throttle and to the mechanism. Each operating position selects a corresponding input to the microprocessor. The engine speed substantially corresponds to predetermined speeds represented by the selected input.
A generator may be operatively connected to the engine for generating electrical power having a magnitude and a frequency. The user manipulated mechanism of the apparatus has a generator operating position. The generator operating position being identified by a mnemonic relating to operation of the generator. The generator operating position selects a predetermined input to the microprocessor and the engine speed substantially corresponds to a predetermined speed represented by the input.
In accordance with a further aspect of the present invention, a method is provided for operating a grass-cutting tractor. The tractor includes an internal combustion engine, a cutting blade for cutting grass, a generator for generating electrical power having a magnitude and frequency, an engine throttle coupled to the engine, an electronic controller having a microprocessor coupled to the throttle, and a user manipulated mechanism having a first grass cutting operating position and a generator operating position. The method includes the steps of selecting one of the operating positions and driving the generator with the engine in response to the selection of the generator operating positions.
The method may include the additional step of driving the cutting blade with the engine in response to the selection of the first grass cutting position. The user manipulated mechanism may also include second and third grass cutting operations positions. The method comprising the further step of operating the engine at an engine speed corresponding to the operating position selected. It is also contemplated to vary the speed of the engine in response to current demand of the generator.
In accordance with a further aspect of the present invention, an improvement in a riding tractor for cutting grass is provided. The riding tractor includes an internal combustion engine having a throttle. The improvement comprises a user manipulated mechanism having plural operating positions. An electrical generator driven by the engine is provided for generating electrical power to power a tool. An electronic controller having a microprocessor is coupled to the throttle and to the mechanism. When the user manipulated mechanism is in a first operating position, the microprocessor regulates the throttle to maintain a substantially constant output voltage produced by the generator. When the user manipulated mechanism is in the second operating position, the microprocessor regulates the throttle to maintain the substantially constant engine speed. The plural operating positions includes first, second and third operating positions. The second and third operating positions select second and third input respectively to the microprocessor. The engine speed substantially corresponds to a predetermined speed represented by the selected input. The second and third operating positions are identified by mnemonics relating to the height of the grass to be cut.